Once on the desktop screen, press the Windows + R keys simultaneously on the keyboard.

In the available field of the opened Run command box, type MSCONFIG and pressEnter.

From the System Configuration box, go to the Boot tab.

Under the Boot options section, check the Safe boot checkbox.

Click OK, and when prompted, click Restart to start Windows 10 in Safe Mode. Alternatively you can also click the Exit without restart button to continue working with the OS, and allow Windows 10 to boot in safe mode the next time the computer starts.

On the other hand, if Windows 10 doesn’t boot properly or no longer allows you to log on with an administrator account, you can enable the legacy Advanced Boot Options menu that allows you to press F8 upon statup. It will display the additional boot options from which you can get to the safe mode in Windows 10.You can enable the Advanced Boot Options menu by following the below instructions.

Power on your PC.

Use the appropriate key(s) to enter into the BIOS setup.

Configure your PC’s BIOS to use CD/DVD drive as the first boot device.

Insert the Windows 10 bootable disc, save the BIOS settings, and restart the computer with the Windows 10 DVD.

On the first displayed screen, click Next, and then click Repair your computerfrom the next box.

Once the first commend executes successfully, type BCDEDIT /SET {DEFAULT} BOOTMENUPOLICY LEGACY command and press Enter.Note: The above command enables the legacy Advanced Boot Options menu that you can access by pressing the F8 key during the computer startup. To disable this, you can follow the above steps, and use the BCDEDIT /SET {DEFAULT} BOOTMENUPOLICY STANDARD command instead and pressEnter.

In the command line-interface itself, this time type EXIT and press Enter.

Eject the inserted Windows 10 bootable disc.

Back on the Choose an option window, click Continue.

Optionally, revert the BIOS settings back to default or set the hard disk drive as the first bootable device, and restart the computer.

Once the computer shuts down and begins to restart, start pressing the F8 key repeatedly until you see the Advanced Boot Options menu.

When displayed, use the arrow keys to go to (highlight) the Safe Mode option and press Enter to start Windows 10 in safe mode.